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	<head>
		<title>three.js webgpu - points instanced</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="example.css">
	</head>

	<body>

		<div id="info">
			<a href="https://threejs.org/" target="_blank" rel="noopener" class="logo-link"></a>

			<div class="title-wrapper">
				<a href="https://threejs.org/" target="_blank" rel="noopener">three.js</a><span>Instanced Points</span>
			</div>

			<small>
				Rendering instanced sprites with TSL to emulate wide points.
			</small>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';
			import { color, storage, Fn, instancedBufferAttribute, instanceIndex, sin, time, float, uniform, shapeCircle, mix, vec3 } from 'three/tsl';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
			import { Inspector } from 'three/addons/inspector/Inspector.js';

			import * as GeometryUtils from 'three/addons/utils/GeometryUtils.js';

			let renderer, scene, camera, camera2, controls, backgroundNode;
			let material;
			let effectController;

			// viewport
			let insetWidth;
			let insetHeight;

			// compute
			let computeSize;

			init();

			async function init() {

				scene = new THREE.Scene();

				camera = new THREE.PerspectiveCamera( 40, window.innerWidth / window.innerHeight, 1, 1000 );
				camera.position.set( - 40, 0, 60 );

				camera2 = new THREE.PerspectiveCamera( 40, 1, 1, 1000 );
				camera2.position.copy( camera.position );

				backgroundNode = color( 0x222222 );

				effectController = {

					pulseSpeed: uniform( 6 ),
					minWidth: uniform( 6 ),
					maxWidth: uniform( 20 )

				};

				// Position and THREE.Color Data

				const points = GeometryUtils.hilbert3D( new THREE.Vector3( 0, 0, 0 ), 20.0, 1, 0, 1, 2, 3, 4, 5, 6, 7 );

				const spline = new THREE.CatmullRomCurve3( points );
				const divisions = Math.round( 4 * points.length );
				const point = new THREE.Vector3();
				const pointColor = new THREE.Color();

				const positions = [];
				const colors = [];
				const sizes = new Float32Array( divisions );

				for ( let i = 0, l = divisions; i < l; i ++ ) {

					const t = i / l;

					spline.getPoint( t, point );
					positions.push( point.x, point.y, point.z );

					pointColor.setHSL( t, 1.0, 0.5, THREE.SRGBColorSpace );
					colors.push( pointColor.r, pointColor.g, pointColor.b );

					sizes[ i ] = 10.0;

				}

				// Instanced Points

				const positionAttribute = new THREE.InstancedBufferAttribute( new Float32Array( positions ), 3 );
				const colorsAttribute = new THREE.InstancedBufferAttribute( new Float32Array( colors ), 3 );

				const instanceSizeBufferAttribute = new THREE.StorageInstancedBufferAttribute( sizes, 1 );
				const instanceSizeStorage = storage( instanceSizeBufferAttribute, 'float', instanceSizeBufferAttribute.count );

				computeSize = Fn( () => {

					const { pulseSpeed, minWidth, maxWidth } = effectController;

					const relativeTime = time.add( float( instanceIndex ) );

					const sizeFactor = sin( relativeTime.mul( pulseSpeed ) ).add( 1 ).div( 2 );

					instanceSizeStorage.element( instanceIndex ).assign( sizeFactor.mul( maxWidth.sub( minWidth ) ).add( minWidth ) );

				} )().compute( divisions );
			
				// Material / Sprites

				const attributeRange = instancedBufferAttribute( instanceSizeBufferAttribute );
				const pointColors = mix( vec3( 0.0 ), instancedBufferAttribute( colorsAttribute ), attributeRange.div( float( effectController.maxWidth ) ) );

				material = new THREE.PointsNodeMaterial( {

					colorNode: pointColors,
					opacityNode: shapeCircle(),
					positionNode: instancedBufferAttribute( positionAttribute ),
					// rotationNode: time,
					sizeNode: instancedBufferAttribute( instanceSizeBufferAttribute ),
					// size: 40, // in pixels units
					vertexColors: true,
					sizeAttenuation: false,
					alphaToCoverage: true

				} );

				const instancedPoints = new THREE.Sprite( material );
				instancedPoints.count = divisions;
				scene.add( instancedPoints );

				// Renderer / Controls

				renderer = new THREE.WebGPURenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				renderer.inspector = new Inspector();
				document.body.appendChild( renderer.domElement );

				controls = new OrbitControls( camera, renderer.domElement );
				controls.enableDamping = true;
				controls.minDistance = 10;
				controls.maxDistance = 500;

				window.addEventListener( 'resize', onWindowResize );
				onWindowResize();

				// GUI

				const gui = renderer.inspector.createParameters( 'Settings' );

				gui.add( material, 'alphaToCoverage' );

				gui.add( effectController.minWidth, 'value', 1, 30, 1 ).name( 'minWidth' );
				gui.add( effectController.maxWidth, 'value', 2, 30, 1 ).name( 'maxWidth' );
				gui.add( effectController.pulseSpeed, 'value', 1, 20, 0.1 ).name( 'pulseSpeed' );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

				insetWidth = window.innerHeight / 4; // square
				insetHeight = window.innerHeight / 4;

				camera2.aspect = insetWidth / insetHeight;
				camera2.updateProjectionMatrix();

			}

			function animate() {

				// compute

				renderer.compute( computeSize );

				// main scene

				renderer.setViewport( 0, 0, window.innerWidth, window.innerHeight );

				controls.update();

				renderer.autoClear = true;

				scene.backgroundNode = null;

				renderer.render( scene, camera );

				// inset scene

				const posY = window.innerHeight - insetHeight - 20;

				renderer.clearDepth(); // important!

				renderer.setScissorTest( true );

				renderer.setScissor( 20, posY, insetWidth, insetHeight );

				renderer.setViewport( 20, posY, insetWidth, insetHeight );

				camera2.position.copy( camera.position );

				camera2.quaternion.copy( camera.quaternion );

				renderer.autoClear = false;

				scene.backgroundNode = backgroundNode;

				renderer.render( scene, camera2 );

				renderer.setScissorTest( false );

			}

			//

		</script>

	</body>

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